Cicada

Description

Cicada is an animal-derived substance used in traditional Chinese medicine (TCM). It is extracted from or prepared by grinding the empty shell shed every seven years by the cicada, (Cryptotympana atrata or Cryptotympana pustulata), which is a winged insect that makes a distinctive chirping sound, and belongs to the Cicadidae family.

Cicadas are commonly found in mainland China, Taiwan, and Japan. They had religious significance in ancient China, and symbolized reincarnation or immortality, as the Chinese compared the cicada's periodic molting of its shell with a person's leaving the physical body behind at the time of death. Bronze vessels as old as 1500 B.C. ornamented with cicadas have been found in Chinese tombs, along with white pottery and jewelry featuring cicada designs. During the Han dynasty (202 B.C. to A.D.) 220, the Chinese carved small cicadas out of precious jade and placed them in the mouths of the dead.

The pharmaceutical name of the substance made from this insect is Periostracum cicadae, or chan tui in Chinese. It is prepared from the exuvium, or cast-off shell of the nymph form of the insect. The empty shell is shiny, translucent, and yellow-brown in color. As it would appear in a living cicada, the shell has three portions: head (with two eyes), chest (with wings and a crossed gap), and abdomen (with three pairs of feet).

General use

The medicinal uses of cicada include treatment of fever and associated seizures; skin rashes; and such eye disorders as conjunctivitis, cataracts, and blurred vision.

Due to its antipyretic effect, cicada-containing preparations are often used to treat high fevers, such as those associated with the common cold or influenza. Western news media reported in April 2003 that the Chinese were using combinations of cicada and silkworm droppings to treat the fever associated with SARS. In addition to reducing fever, cicada is also used in TCM to treat other symptoms of colds and flu, including laryngitis, headache, restless sleep, or nightmares.

Cicada is said to be effective in relieving itchy rashes and eczema. Its special use is for the treatment of rashes or skin eruptions that occur in the early stages of measles or chicken pox. According to traditional Chinese medicine, the sooner the rashes appear, the shorter and less severe these diseases will be. Therefore, a Chinese herbalist may suggest cicada preparations to hasten the eruption of the rash.

Cicada is said to prevent or reduce muscle spasms by reducing the tension of the striated muscles. It may also delay transmission of nerve signals at the neuromuscular junction, thereby reducing muscle spasms. Its actions may be similar to those of Western barbiturates, sedatives, and anticonvulsants (antiseizure medications).

Cicada has also been used in TCM to treat eye diseases associated with wind and heat, including blurred vision and conjunctivitis (inflammation of the membrane that lines the eyelids). It is usually mixed with chrysanthemum flowers (Chrysanthemum morifolium, or ju hua in Chinese) when used to treat cataracts.

Preparations

The usual dosage of cicada when taken alone is 3–9 grams per day. As of 2004, whole cicadas cost about 10 cents per gram when purchased in bulk from suppliers of Chinese medicinal herbs. Cicada may be prepared as a decoction, which means that the insect shells are boiled down to a concentrated broth or tea to be taken internally. Other forms of cicada preparations include ground powder and water and alcohol extracts.

Precautions

A general precaution when using herbs or other alternative medicines is to purchase them only from reputable sources. In the case of traditional Chinese remedies, this precaution is particularly important because many of them are imported from countries without strict production or labeling standards. In the case of cicada, the United States Food and Drug Administration (FDA) reported in June 2003 that a shipment described as "Cicada Molting Herbal Food Supplement" from Taiwan was refused entry into the United States and considered dangerous. In this instance, the FDA defined "dangerous" in these terms: "The article appears to be dangerous to health when used in the dosage or manner, or with the frequency or duration, prescribed, recommended, or suggested in the labeling thereof."

Practitioners of TCM state that pregnant women should not use cicada because of the risk of miscarriage.

Side effects

No side effects from cicada preparations have been reported in the United States as of early 2004.

Interactions

As of 2004, cicada decoctions have not been reported to interact with any Western prescription medications.

OTHER

Food and Drug Administration (FDA). "Refusal Actions by FDA as Recorded in OASIS (Organization for the Advancement of Structured Information Standards), Taiwan, Republic of China." Rockville, MD: FDA, June 2003. <http://www.fda.gov/ora/oasis/6/ora_oasis_c_tw.html>.